Tube cap



FIG. 1 is a side view of a tube cap showing our new design. No figures depict the remaining sides, since these views of the design are identical to the side view shown.

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof; and,

FIG. 4 is a bottom perspective view thereof, it being understood that the interior sides of the bottom portion of the tube cap not shown are identical to those shown. 

The ornamental design for a tube cap, as shown and described. 